Thin film deposition apparatus

ABSTRACT

A thin film deposition apparatus can be simply applied to produce large-sized display devices on a mass scale and improves manufacturing yield. The thin film deposition apparatus for forming a thin film on a substrate includes: a deposition source that discharges a deposition material; a deposition source nozzle unit disposed at a side of the deposition source and including a plurality of deposition source nozzles arranged in a first direction; and a patterning slit sheet disposed opposite to the deposition source nozzle unit and including a plurality of patterning slits arranged in the first direction; wherein each of the patterning slits includes a plurality of sub-slits.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Korean Application Nos.10-2009-0099314, filed on Oct. 19, 2009 and 10-2010-0014277, filed onFeb. 17, 2010, in the Korean Intellectual Property Office, thedisclosures of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

A thin film deposition apparatus that can be simply applied to producelarge-sized display devices on a mass scale and that improvesmanufacturing yield.

2. Description of the Related Art

Organic light-emitting display devices have a larger viewing angle,better contrast characteristics, and a faster response rate than otherdisplay devices, and thus have drawn attention as next-generationdisplay devices.

Organic light-emitting display devices generally have a stackedstructure including an anode, a cathode, and an emission layerinterposed between the anode and the cathode. The devices display imagesin color when holes and electrons, injected respectively from the anodeand the cathode, recombine in the emission layer and thus light isemitted. However, it is difficult to achieve high light-emissionefficiency with such a structure, and thus intermediate layers,including an electron injection layer, an electron transport layer, ahole transport layer, a hole injection layer, or the like, areoptionally additionally interposed between the emission layer and eachof the electrodes.

Also, it is practically very difficult to form fine patterns in organicthin films such as the emission layer and the intermediate layers, andred, green, and blue light-emission efficiency varies according to theorganic thin films. For these reasons, it is not easy to form an organicthin film pattern on a large substrate, such as a mother glass having asize of 5 G or more, by using a conventional thin film depositionapparatus, and thus it is difficult to manufacture large organiclight-emitting display devices having satisfactory driving voltage,current density, brightness, color purity, light-emission efficiency, orlife-span characteristics. Thus, there is a demand for improvement inthis regard.

An organic light-emitting display device includes intermediate layers,including an emission layer disposed between a first electrode and asecond electrode where the electrodes are arranged opposite to eachother. The interlayer and the first and second electrodes may be formedusing a variety of methods, one of which is a deposition method. When anorganic light-emitting display device is manufactured by using thedeposition method, a fine metal mask (FMM) having the same pattern asthe thin film to be formed is disposed to closely contact a substrate,and a thin film material is deposited over the FMM in order to form thethin film having the desired pattern.

SUMMARY OF THE INVENTION

Aspects of the present invention provide a thin film depositionapparatus that may be easily manufactured, that may be simply applied toproduce large-sized display devices on a mass scale, that improvesmanufacturing yield and deposition efficiency, and that allows depositedmaterials to be reused.

An aspect of the present invention provides a thin film depositionapparatus for forming a thin film on a substrate, the apparatusincluding: a deposition source that discharges a deposition material; adeposition source nozzle unit disposed at a side of the depositionsource and including a plurality of deposition source nozzles arrangedin a first direction; and a patterning slit sheet disposed opposite tothe deposition source nozzle unit and including a plurality ofpatterning slits arranged in the first direction; wherein each of thepatterning slits includes a plurality of sub-slits.

The gap between the neighboring patterning slits may be greater than thegap between the neighboring sub-slits included in one patterning slit.

The sub-slits may be arranged so that at least a part of the patternthat is formed of the deposition material discharged from one of thesub-slits included in one patterning slit towards the substrate and atleast a part of the pattern that is formed of the deposition materialdischarged from the other of the sub-slits included in one patterningslit towards the substrate may overlap each other.

The plurality of sub-slits may be rectangles arranged in parallel witheach other.

The plurality of sub-slits may be holes arranged in a plurality of rowswhich are in parallel with each other.

The thin film deposition apparatus may be separate from the substrate bya predetermined distance, and the substrate may be movable relative tothe thin film deposition apparatus.

The deposition materials contained in the deposition sources of the thinfilm deposition apparatus may be continuously deposited on the substratewhile the substrate or the thin film deposition apparatus is movedrelative to the other.

The thin film deposition apparatus or the substrate may be movablerelative to the other along a plane parallel to a surface of thesubstrate on which the deposition materials are deposited.

The patterning slit sheet of the thin film deposition apparatus may besmaller than the substrate.

The total number of the patterning slits may be greater than a totalnumber of the deposition source nozzles.

According to another aspect of the present invention, a thin filmdeposition apparatus for forming a thin film on a substrate, includes: adeposition source that discharges a deposition material; a depositionsource nozzle unit disposed at a side of the deposition source andincluding a plurality of deposition source nozzles arranged in a firstdirection; and a patterning slit sheet disposed opposite to thedeposition source nozzle unit and including a plurality of patterningslits arranged in a second direction perpendicular to the firstdirection, wherein a deposition is performed while the substrate or thethin film deposition apparatus moves relative to the other in the firstdirection, the deposition source, the deposition source nozzle unit, andthe patterning slit sheet are formed integrally with each other, andeach of the patterning slits includes a plurality of sub-slits.

The gap between the neighboring patterning slits may be greater than thegap between the neighboring sub-slits included in one patterning slit.

The sub-slits may be arranged so that at least a part of the patternthat is formed of the deposition material discharged from one of thesub-slits included in one patterning slit towards the substrate and atleast a part of the pattern that is formed of the deposition materialdischarged from the other of the sub-slits included in one patterningslit towards the substrate may overlap each other.

The plurality of sub-slits may be formed as rectangles arranged inparallel with each other.

The plurality of sub-slits may be holes arranged in a plurality of rowswhich are parallel with each other.

The deposition source, the deposition source nozzle unit, and thepatterning slit sheet may be connected to each other by a connectionmember.

The connection member may guide movement of the discharged depositionmaterial.

The connection member may seal a space between the deposition source andthe deposition source nozzle unit, and the patterning slit sheet.

The thin film deposition apparatus may be separate from the substrate bya predetermined distance.

The deposition material discharged from the thin film depositionapparatus may be continuously deposited on the substrate while thesubstrate or the thin film deposition apparatus is moved relative to theother in the first direction.

The patterning slit sheet of the thin film deposition apparatus may besmaller than the substrate.

The plurality of deposition source nozzles may be tilted at apredetermined angle.

The plurality of deposition source nozzles may include deposition sourcenozzles arranged in two rows formed in the first direction, and thedeposition source nozzles in the two rows may tilt to face each other.

The plurality of deposition source nozzles may include deposition sourcenozzles arranged in two rows formed in the first direction, thedeposition source nozzles arranged in a row located at a first side ofthe patterning slit sheet may be arranged to face a second side of thepatterning slit sheet, and the deposition source nozzles arranged in theother row located at the second side of the patterning slit sheet may bearranged to face the first side of the patterning slit sheet.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a schematic perspective view of a thin film depositionapparatus according to an embodiment of the present invention.

FIG. 2 is a schematic side view of the thin film deposition apparatus ofFIG. 1;

FIG. 3 is a schematic plan view of the thin film deposition apparatus ofFIG. 1;

FIG. 4A is a cross-sectional view of a pattern formed in a fine metalmask (FMM);

FIG. 4B is a cross-sectional view of a pattern when a substrate and apatterning slit sheet are separate from each other and a single slitforms a patterning slit, according to an embodiment of the presentinvention;

FIG. 5A is a plan view of a patterning slit sheet in the thin filmdeposition apparatus of FIG. 1;

FIG. 5B is a cross-sectional view showing the patterning slit sheet ofFIG. 5A and a pattern formed by the patterning slit sheet of FIG. 1;

FIG. 5C is a graph showing experimental results when a new pattern wasformed by overlapping a plurality of patterns, according to theembodiment of FIG. 1;

FIG. 6A is a plan view of a patterning slit sheet in a thin filmdeposition apparatus according to a modified example of the embodimentof FIG. 1;

FIG. 6B is a cross-sectional view of the patterning slit sheet of FIG.6A and a pattern formed by the patterning slit sheet;

FIGS. 7A and 7B are plan views of patterning slit sheets in a thin filmdeposition apparatus, according to other modified examples of theembodiment of FIG. 1;

FIG. 8 is a schematic cross-sectional view of an organic light-emittingdisplay device manufactured by using a thin film deposition apparatus,according to another embodiment of the present invention;

FIG. 9 is a schematic perspective view of a thin film depositionapparatus according to another embodiment of the present invention;

FIG. 10 is a schematic side view of the thin film deposition apparatusof FIG. 9;

FIG. 11 is a schematic plan view of the thin film deposition apparatusof FIG. 9;

FIG. 12 is a schematic perspective view of the thin film depositionapparatus according to another embodiment of the present invention;

FIG. 13 is a graph schematically illustrating a thickness distributionof a layer formed on a substrate when a deposition source nozzle was nottilted, in a thin film deposition apparatus according to anotherembodiment of the present invention; and

FIG. 14 is a graph schematically illustrating a thickness distributionof a layer formed on a substrate when a deposition source nozzle wastilted, in a thin film deposition apparatus according to the embodimentof FIG. 13.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures. Moreover, it is to beunderstood that where is stated herein that one structure is “formed on”or “disposed on” a second structure, the first structure may be formedor disposed directly on the second structure or there may be anintervening structure between the first structure and the secondstructure. Further, as used herein, the term “formed on” or “disposedon” are used with the same meaning as “located on” and are not meant tobe limiting regarding any particular fabrication process

FIG. 1 is a schematic perspective view of a thin film depositionapparatus 100 according to an embodiment of the present invention, FIG.2 is a schematic side view of the thin film deposition apparatus 100,and FIG. 3 is a schematic plan view of the thin film depositionapparatus 100. Referring to FIGS. 1, 2 and 3, the thin film depositionapparatus 100 according to the current embodiment of the presentinvention includes a deposition source 110, a deposition source nozzleunit 120, and a patterning slit sheet 150.

Although a chamber is not illustrated in FIGS. 1, 2 and 3 forconvenience of explanation, all the components of the thin filmdeposition apparatus 100 may be disposed within a chamber that ismaintained at an appropriate degree of vacuum. The chamber is maintainedat an appropriate vacuum in order to allow a deposition material to movein a substantially straight line through the thin film depositionapparatus 100.

In particular, in order to deposit a deposition material 115 that isemitted from the deposition source 110 and is discharged through thedeposition source nozzle unit 120 and the patterning slit sheet 150,onto a substrate 400 in a desired pattern, it is required to maintainthe chamber in a high-vacuum state as in a deposition method using afine metal mask (FMM). In addition, the temperature of the patterningslit sheet 150 has to be sufficiently lower than the temperature of thedeposition source 110. In this regard, the temperature of the patterningslit sheet 150 may be about 100° C. or less. The temperature of thepatterning slit sheet 150 should be sufficiently low so as to reducethermal expansion of the patterning slit sheet 150.

The substrate 400, which constitutes a target on which a depositionmaterial 115 is to be deposited, is disposed in the chamber. Thesubstrate 400 may be a substrate for flat panel displays. A largesubstrate, such as a mother glass, for manufacturing a plurality of flatpanel displays may be used as the substrate 400. Other substrates mayalso be employed. In the current embodiment of the present invention,deposition may be performed while the substrate 400 or the thin filmdeposition apparatus 100 is moved relative to the other.

In particular, in the conventional FMM deposition method, the size ofthe FMM has to be equal to the size of a substrate. Thus, the size ofthe FMM has to be increased as the substrate becomes larger. However, itis neither straightforward to manufacture a large FMM nor to extend anFMM and still have the FMM be accurately aligned with a pattern.

In order to overcome this problem, in the thin film deposition apparatus100 according to the current embodiment of the present invention,deposition may be performed while the thin film deposition apparatus 100or the substrate 400 is moved relative to the other. In other words,deposition may be continuously performed while the substrate 400, whichis disposed so as to face the thin film deposition apparatus 100, ismoved in the Y-axis direction. In other words, for example, depositionis performed in a scanning manner while the substrate 400 is moved inthe direction of arrow A in FIGS. 1 and 3. Although the substrate 400 isillustrated as being moved in the Y-axis direction in FIGS. 1 and 3 whendeposition is performed, the present invention is not limited thereto.For example, deposition may be performed while the thin film depositionapparatus 100 is moved in the Y-axis direction, whereas the substrate400 is fixed.

Thus, in the thin film deposition apparatus 100 according to the currentembodiment of the present invention, the patterning slit sheet 150 maybe significantly smaller than an FMM used in a conventional depositionmethod. In other words, in the thin film deposition apparatus 100according to the current embodiment of the present invention, depositionis continuously performed, i.e., in a scanning manner, while thesubstrate 400 is moved in the Y-axis direction. Thus, lengths of thepatterning slit sheet 150 in the X-axis and Y-axis directions may besignificantly less than the lengths of the substrate 400 in the X-axisand Y-axis directions. As described above, since the patterning slitsheet 150 may be formed to be significantly smaller than an FMM used ina conventional deposition method, it is relatively easy to manufacturethe patterning slit sheet 150 used in aspects of the present invention.In other words, using the patterning slit sheet 150, which is smallerthan an FMM used in a conventional deposition method, is more convenientin all processes, including etching and subsequent other processes, suchas precise extension, welding, moving, and cleaning processes, comparedto the conventional deposition method using the larger FMM. This is moreadvantageous for a relatively large display device.

In order to perform deposition while the thin film deposition apparatus100 or the substrate 400 is moved relative to the other as describedabove, the thin film deposition apparatus 100 and the substrate 400 maybe separate from each other by a predetermined distance. This will bedescribed later in detail.

The deposition source 110 that contains and heats the depositionmaterial 115 is disposed in an opposite side of the chamber to that inwhich the substrate 400 is disposed. As the deposition material 115contained in the deposition source 110 is vaporized, the depositionmaterial 115 is deposited on the substrate 400.

In particular, the deposition source 110 includes a crucible 111 that isfilled with the deposition material 115, and a heater 112 that heats thecrucible 111 to vaporize the deposition material 115 that is containedin the crucible 111 toward a side of the crucible 111, and inparticular, toward the deposition source nozzle unit 120.

The deposition source nozzle unit 120 is disposed at a side of thedeposition source 110, and in particular, at the side of the depositionsource 110 facing the substrate 400. The deposition source nozzle unit120 includes a plurality of deposition source nozzles 121 arranged atequal intervals in the X-axis direction. The deposition material 115that is vaporized in the deposition source 110 passes through thedeposition source nozzle unit 120 toward the substrate 400 that is adeposition target.

The patterning slit sheet 150 and a frame 155 in which the patterningslit sheet 150 is held are disposed between the deposition source 110and the substrate 400. The frame 155 may be formed in a lattice shape,similar to a window frame. The patterning slit sheet 150 is held insidethe frame 155. The patterning slit sheet 150 includes a plurality ofpatterning slits 151 arranged in the X-axis direction. That is, thepatterning slits 151 are parallel to each other, and the resultingdeposition pattern is generally rectangular. The deposition material 115that is vaporized in the deposition source 110 passes through thedeposition source nozzle unit 120 and the patterning slit sheet 150toward the substrate 400. The patterning slit sheet 150 may bemanufactured by etching, which is the same method as used in aconventional method of manufacturing an FMM, and in particular, astriped FMM. Here, the total number of patterning slits 151 may begreater than the total number of deposition source nozzles 121.

In the thin film deposition apparatus 100 of the current embodiment ofthe present invention, each of the patterning slits 151 includes aplurality of sub-slits 151 a and 151 b. As described above, each of thepatterning slits 151 includes the plurality of sub-slits 151 a and 151b, and when the sub-slits 151 a and 151 b are arranged so that patternsformed by the plurality of sub-slits 151 a and 151 b overlap each other,desired patterns may be obtained. This will be described later indetail.

In addition, the deposition source 110 (and the deposition source nozzleunit 120 coupled to the deposition source 110) and the patterning slitsheet 150 may be formed to be separate from each other by apredetermined distance. Alternatively, the deposition source 110 (andthe deposition source nozzle unit 120 coupled to the deposition source110) and the patterning slit sheet 150 may be connected by a connectionmember 135.

As described above, the thin film deposition apparatus 100 according tothe current embodiment of the present invention performs depositionwhile being moved relative to the substrate 400. In order to move thethin film deposition apparatus 100 relative to the substrate 400, thepatterning slit sheet 150 is separate from the substrate 400 by apredetermined distance. In addition, when the patterning slit sheet 150and the substrate 400 are separate from each other by a predetermineddistance, a shadow zone may be generated on the substrate 400 and thedesired pattern may not be obtained. In order to overcome the aboveand/or other problems, according to the thin film deposition apparatus100 of the current embodiment, one patterning slit 151 includes theplurality of sub-slits 151 a and 151 b, and the desired pattern isformed by overlapping the patterns formed by the plurality of sub-slits151 a and 151 b

In particular, in a conventional deposition method using an FMM,deposition is performed with the FMM in close contact with a substratein order to prevent formation of a shadow zone on the substrate.However, when the FMM is used in close contact with the substrate, thecontact may cause defects. In addition, in the conventional depositionmethod, the size of the mask has to be the same as the size of thesubstrate since the mask cannot be moved relative to the substrate.Thus, the size of the mask has to be increased as display devices becomelarger. However, it is not easy to manufacture such a large mask.

In order to overcome this problem, in the thin film deposition apparatus100 according to the current embodiment of the present invention, thepatterning slit sheet 150 is disposed to be separate by a predetermineddistance from the substrate 400 that is the deposition target. This isrealized by forming each of the patterning slits 151 to include a pairof sub-slits 151 a and 151 b, and forming the desired pattern by usingthe overlapping of the patterns formed by the pair of sub-slits 151 aand 151 b.

As described above, according to these aspects of the present invention,a mask is formed to be smaller than a substrate, and deposition isperformed while the mask is moved relative to the substrate. Thus, themask can be easily manufactured. In addition, defects caused due to thecontact between a substrate and an FMM, which occurs in the conventionaldeposition method, may be prevented. In addition, since it isunnecessary to use the FMM in close contact with the substrate during adeposition process, the manufacturing speed may be improved.

Hereinafter, a pattern formed in the conventional method using the FMM,a pattern formed when the substrate 400 is separate from the patterningslit sheet 150 by a predetermined distance and the patterning slit is asingle slit, and a pattern formed when the substrate 400 is separatefrom the patterning slit sheet 150 and the patterning slit includes aplurality of sub-slits will be compared with each other in detail.

As shown in FIG. 4A, a mask 150′ and the substrate 400 are in closecontact to each other in the conventional method using the FMM.Therefore, a shadow zone is not generated on the substrate 400 and adesired pattern PS1 may be obtained. However, when the FMM is used inclose contact with the substrate, the contact may cause defects. Inaddition, in the conventional deposition method using the FMM, the sizeof the mask has to be the same as the size of the substrate since themask cannot be moved relative to the substrate.

On the other hand, as shown in FIG. 4B, when the patterning slit is asingle slit, a mask 150″ having a size that is less than that of thesubstrate 400 is formed, and then, the deposition is performed whilemoving the mask 150″ relative to the substrate 400. Thus, it is easy tofabricate the mask 150″, and defects caused due to the close contactbetween the substrate 400 and the mask 150″ may be prevented. However,in this case, since the mask 150″ is separate by a predetermineddistance from the substrate 400, a shadow zone is inevitably generatedon the substrate 400, and thus, a desired pattern PS2 may not be formed.

To overcome the above problem, in the thin film deposition apparatus 100according to the current embodiment of the present invention, onepatterning slit 151 is formed by using a plurality of sub-slits 151 aand 151 b, and the desired pattern is formed by using overlapping of thepatterns formed through the plurality of sub-slits 151 a and 151 b. Thatis, as shown in FIG. 5A, one patterning slit 151 includes two sub-slits151 a and 151 b. That is, the gap between two neighboring patterningslits 151 is greater than a gap between two neighboring sub-slits 151 aand 151 b that form one patterning slit 151.

FIG. 5B shows a pattern formed through the patterning slit sheet 150.That is, the pattern formed of the deposition material dischargedthrough the first sub-slit 151 a toward the substrate 400 and thepattern formed of the deposition material discharged through the secondsub-slit 151 b toward the substrate 400 are formed so that at least someparts of the patterns overlap each other. The upper end portion of theoverlap pattern becomes flat due to the spreading effect of vaporizedparticles, and consequently, a single pattern PS3 of a predeterminedshape is formed, which is similar to the pattern PS1 formed by thedeposition method using the FMM.

FIG. 5C is a graph illustrating experimental results when a new patternwas formed by overlapping a plurality of patterns with each other. Asshown in FIG. 5C, two patterns B and C that were formed by twoneighboring sub-slits that combined to form a new type pattern D.

Although one patterning slit 151 includes two sub-slits 151 a and 151 bin FIGS. 5A and 5B, the present invention is not limited thereto. Thatis, one patterning slit 151 may include two or more sub-slits. Thenumber of the sub-slits, the gap between the sub-slits, and the gapbetween the patterning slits may be dependent upon the shape of thedesired pattern.

For example, as shown in FIG. 6A, one patterning slit 151 may includefive sub-slits 151 a, 151 b, 151 c, 151 d, and 151 e that are parallelto each other. Here, the pattern formed of the deposition materialdeposited on the substrate 400 through each of the sub-slits overlapsthe pattern formed of the deposition material deposited on the substrate400 through the neighboring sub-slit by at least a part. The upperportion of the overlapped pattern becomes flat due to the spreadingeffect of vaporized particles, and consequently, a single pattern PS4 ofa predetermined shape is formed, which is similar to the pattern PS1formed by the conventional deposition method using the FMM. Thepredetermined shape is generally a rectangle. Otherwise, as shown inFIGS. 7A and 7B, the patterning slit may include a plurality ofsub-slits formed as holes, and thus, a square or other desired shapepattern may be formed.

According to this embodiment of the present invention, the desiredpattern may be formed even when the substrate and the mask are separatefrom each other by the predetermined distance, and thus, the mask may beeasily fabricated, defects caused by close contact between the substrateand the mask may be prevented, and the fabricating speed of the thinfilm deposition apparatus may be improved.

FIG. 8 is a cross-sectional view of an active matrix organic lightemitting display device fabricated by using a thin film depositionapparatus, according to another embodiment of the present invention.Referring to FIG. 8, a buffer layer 51 is formed on a substrate 50formed of glass or plastic. A thin film transistor (TFT) and an organiclight emitting diode (OLED) are formed on the buffer layer 51.

An active layer 52 having a predetermined pattern is formed on thebuffer layer 51 of the substrate 50. A gate insulating layer 53 isformed on the active layer 52, and a gate electrode 54 is formed in apredetermined region of the gate insulating layer 53. The gate electrode54 is connected to a gate line (not shown) that applies ON/OFF signalsto the TFT. An interlayer insulating layer 55 is formed on the gateelectrode 54. Source/drain electrodes 56 and 57 are formed such as tocontact source/drain regions 52 b and 52 c, respectively, of the activelayer 52 through contact holes. A passivation layer 58 is formed ofSiO₂, SiN_(x), or the like, on the source/drain electrodes 56 and 57. Aplanarization layer 59 is formed of an organic polymeric material, suchas an acrylic, a polyimide, benzocyclobutene (BCB) polymer, or the like,on the passivation layer 58. A pixel electrode 61, which functions as ananode of the OLED, is formed on the planarization layer 59, and a pixeldefining layer 60 formed of an organic material is formed to cover thepixel electrode 61. An opening is formed in the pixel defining layer 60,and an organic layer 62 is formed on the surface of the pixel defininglayer 60 and on the surface of the pixel electrode 61 exposed throughthe opening. The organic layer 62 includes an emission layer. Thepresent invention is not limited to the structure of the organiclight-emitting display device described above, and various structures oforganic light-emitting display devices may be used in the presentinvention.

The OLED displays predetermined image information by emitting red, greenand blue light as current flows. The OLED includes the pixel electrode61, which is connected to the drain electrode 56 of the TFT and to whicha positive power voltage is applied, a counter electrode 63, which isformed so as to cover the entire sub-pixel and to which a negative powervoltage is applied, and the organic layer 62, which is disposed betweenthe pixel electrode 61 and the counter electrode 63 to emit light. Thepixel electrode 61 and the counter electrode 63 are insulated from eachother by the organic layer 62, and respectively apply voltages ofopposite polarities to the organic layer 62 to induce light emission inthe organic layer 62.

The organic layer 62 may include a low-molecular weight organic layer ora high-molecular weight organic layer. When a low-molecular weightorganic layer is used as the organic layer 62, the organic layer 62 mayhave a single or multi-layer structure including at least one selectedfrom the group consisting of a hole injection layer (HIL), a holetransport layer (HTL), an emission layer (EML), an electron transportlayer (ETL), and an electron injection layer (EIL). Examples ofavailable organic materials include copper phthalocyanine (CuPc),N,N′-di(naphthalene-1-yl)-N,N′-diphenyl-benzidine ({acute over(α)}-NPB), tris-8-hydroxyquinoline aluminum (Alq3), and the like. Thelow-molecular weight organic layer may be formed by vacuum deposition.

When a high-molecular weight organic layer is used as the organic layer62, the organic layer 62 may mostly have a structure including a HTL andan EML. In this case, the HTL may be formed ofpoly(ethylenedioxythiophene) (PEDOT), and the EML may be formed ofpolyphenylenevinylenes (PPVs) or polyfluorenes. The HTL and the EML maybe formed by screen printing, inkjet printing, or the like. The organiclayer 62 is not limited to the organic layers described above, and maybe embodied in various ways.

The pixel electrode 61 functions as an anode, and the counter electrode63 functions as a cathode. Alternatively, the pixel electrode 61 mayfunction as a cathode, and the counter electrode 63 may function as ananode.

The pixel electrode 61 may be formed as a transparent electrode or areflective electrode. Such a transparent electrode may be formed ofindium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), orindium oxide (In₂O₃). Such a reflective electrode may be formed byforming a reflective layer from silver (Ag), magnesium (Mg), aluminum(Al), platinum (Pt), palladium (Pd), gold (Au), nickel (Ni), neodymium(Nd), iridium (Ir), chromium (Cr) or a compound thereof and forming alayer of ITO, IZO, ZnO, or In₂O₃ on the reflective layer.

The counter electrode 63 may be formed as a transparent electrode or areflective electrode. When the counter electrode 63 is formed as atransparent electrode, the counter electrode 63 functions as a cathode.To this end, such a transparent electrode may be formed by depositing ametal having a low work function, such as lithium (Li), calcium (Ca),lithium fluoride/calcium (LiF/Ca), lithium fluoride/aluminum (LiF/Al),aluminum (Al), silver (Ag), magnesium (Mg), or a compound or mixturethereof on a surface of the organic layer 62 and forming an auxiliaryelectrode layer or a bus electrode line thereon from a transparentelectrode forming material, such as ITO, IZO, ZnO, In₂O₃, or the like.When the counter electrode 63 is formed as a reflective electrode, thereflective layer may be formed by depositing Li, Ca, LiF/Ca, LiF/Al, Al,Ag, Mg, or a compound thereof on the entire surface of the organic layer62.

In the organic light-emitting display apparatus described above, theorganic layer 62 including the emission layer may be formed by using athin film deposition apparatus 100 (see FIG. 1), which is describedabove. The thin film deposition apparatuses according to the embodimentsof the present invention described above may be applied to form anorganic layer or an inorganic layer of an organic TFT, and to formlayers from various materials.

FIG. 9 is a schematic perspective view of a thin film depositionapparatus 900 according to another embodiment of the present invention,FIG. 10 is a schematic side view of the thin film deposition apparatus900, and FIG. 11 is a schematic plan view of the thin film depositionapparatus 900.

Referring to FIGS. 9, 10 and 11, the thin film deposition apparatus 900according to the current embodiment of the present invention includes adeposition source 910, a deposition source nozzle unit 920, and apatterning slit sheet 950. Although a chamber is not illustrated inFIGS. 9, 10 and 11 for convenience of explanation, all the components ofthe thin film deposition assembly 900 may be disposed within a chamberthat is maintained at an appropriate degree of vacuum. The chamber ismaintained at an appropriate vacuum in order to allow a depositionmaterial to move in a substantially straight line through the thin filmdeposition apparatus 900.

In particular, in order to deposit a deposition material 915 that isemitted from the deposition source 910 and is discharged through thedeposition source nozzle unit 920 and the patterning slit sheet 950,onto a substrate 400 in a desired pattern, it is required to maintainthe chamber in a high-vacuum state as in a deposition method using afine metal mask (FMM). In addition, the temperature of the patterningslit sheet 950 has to be sufficiently lower than the temperature of thedeposition source 910. In this regard, the temperature of the patterningslit sheet 150 may be about 100° C. or less. The temperature of thepatterning slit sheet 950 should be sufficiently low so as to reducethermal expansion of the patterning slit sheet 950.

The substrate 400, which constitutes a target on which a depositionmaterial 915 is to be deposited, is disposed in the chamber. Thesubstrate 400 may be a substrate for flat panel displays. A largesubstrate, such as a mother glass, for manufacturing a plurality of flatpanel displays, may be used as the substrate 400. Other substrates mayalso be employed.

In the current embodiment of the present invention, deposition may beperformed while the substrate 400 or the thin film deposition assembly900 is moved relative to the other. In particular, in the conventionalFMM deposition method, the size of the FMM has to be equal to the sizeof a substrate. Thus, the size of the FMM has to be increased as thesubstrate becomes larger. However, it is neither straightforward tomanufacture a large FMM nor to extend an FMM to have the FMM beaccurately aligned with a pattern.

In order to overcome this problem, in the thin film deposition assembly900 according to the current embodiment of the present invention,deposition may be performed while the thin film deposition assembly 900or the substrate 400 is moved relative to the other. In other words,deposition may be continuously performed while the substrate 400, whichis disposed such as to face the thin film deposition assembly 900, ismoved in a Y-axis direction. In other words, deposition is performed ina scanning manner while the substrate 400 is moved in the direction ofarrow A in FIG. 9. Although the substrate 400 is illustrated as beingmoved in the Y-axis direction in FIG. 9 when deposition is performed,the present invention is not limited thereto. Deposition may beperformed while the thin film deposition assembly 900 is moved in theY-axis direction, whereas the substrate 400 is fixed.

Thus, in the thin film deposition assembly 900 according to the currentembodiment of the present invention, the patterning slit sheet 950 maybe significantly smaller than an FMM used in a conventional depositionmethod. In other words, in the thin film deposition assembly 900according to the current embodiment of the present invention, depositionis continuously performed, i.e., in a scanning manner while thesubstrate 400 is moved in the Y-axis direction. Thus, lengths of thepatterning slit sheet 950 in the X-axis and Y-axis directions may besignificantly less than the lengths of the substrate 400 in the X-axisand Y-axis directions. As described above, since the patterning slitsheet 950 may be formed to be significantly smaller than an FMM used ina conventional deposition method, it is relatively easy to manufacturethe patterning slit sheet 950 used in the present invention. In otherwords, using the patterning slit sheet 950, which is smaller than an FMMused in a conventional deposition method, is more convenient in allprocesses, including etching of the patterning slit sheet 950 andsubsequent other processes, such as precise extension, welding, moving,and cleaning processes, compared to the conventional deposition methodusing the larger FMM. This is more advantageous for a relatively largedisplay device.

In order to perform deposition while the thin film deposition assembly900 or the substrate 400 is moved relative to the other as describedabove, the thin film deposition assembly 900 and the substrate 400 maybe separate from each other by a predetermined distance. This will bedescribed later in detail.

The deposition source 910 that contains and heats the depositionmaterial 915 is disposed in an opposite side of the chamber to that inwhich the substrate 400 is disposed. As the deposition material 915contained in the deposition source 910 is vaporized, the depositionmaterial 915 is deposited on the substrate 400.

In particular, the deposition source 910 includes a crucible 911 that isfilled with the deposition material 915, and a heater 912 that heats thecrucible 911 to vaporize the deposition material 915, which is containedin the crucible 911, towards a side of the crucible 911, and inparticular, towards the deposition source nozzle unit 920.

The deposition source nozzle unit 920 is disposed at a side of thedeposition source 910, and in particular, at the side of the depositionsource 910 facing the substrate 400. The deposition source nozzle unit920 includes a plurality of deposition source nozzles 921 arranged atequal intervals in the Y-axis direction. The deposition material 915that is vaporized in the deposition source 910, passes through thedeposition source nozzle unit 920 towards the substrate 400 that is thedeposition target. As described above, when the plurality of depositionsource nozzles 921 are formed on the deposition source nozzle unit 920in the Y-axis direction, that is, the scanning direction of thesubstrate 400, the size of the pattern formed by the deposition materialthat is discharged through each of patterning slits 951 in thepatterning slit sheet 950 is only affected by the size of one depositionsource nozzle 921, that is, it may be considered that one depositionnozzle 921 exists in the X-axis direction, and thus there is no shadowzone on the substrate 400. In addition, since the plurality ofdeposition source nozzles 921 are formed in the scanning direction ofthe substrate 400, even though there is a difference between fluxes ofthe deposition source nozzles 921, the difference may be compensated anddeposition uniformity may be maintained constantly.

The patterning slit sheet 950 and a frame 955 in which the patterningslit sheet 950 is bound are disposed between the deposition source 910and the substrate 400. The frame 955 may be formed in a lattice shape,similar to a window frame. The patterning slit sheet 950 is bound insidethe frame 955. The patterning slit sheet 950 includes a plurality ofpatterning slits 951 arranged in the X-axis direction. The depositionmaterial 915 that is vaporized in the deposition source 910, passesthrough the deposition source nozzle unit 920 and the patterning slitsheet 950 toward the substrate 400. The patterning slit sheet 950 may bemanufactured by etching, which is the same method as used in aconventional method of manufacturing an FMM, and in particular, astriped FMM. Here, the total number of patterning slits 951 may begreater than the total number of deposition source nozzles 921.

On the other hand, the deposition source 910 (and the deposition sourcenozzle unit 920 coupled to the deposition source 910) and the patterningslit sheet 950 may be formed to be separate from each other by apredetermined distance. Alternatively, the deposition source 910 (andthe deposition source nozzle unit 920 coupled to the deposition source910) and the patterning slit sheet 950 may be connected by connectionmembers 935. That is, the deposition source 910, the deposition sourcenozzle unit 920, and the patterning slit sheet 950 may be formedintegrally with each other by being connected to each other via theconnection members 935. The connection member 935 guides the depositionmaterial 915, which is discharged through the deposition source nozzles921, to move straight, not to flow in the X-axis direction. In FIGS. 9through 11, the connection members 935 are formed on left and rightsides of the deposition source 910, the deposition source nozzle unit920, and the patterning slit sheet 950 to guide the deposition material915 not to flow in the X-axis direction, however, the present inventionis not limited thereto. That is, the connection member 935 may be formedas a sealed type of a box shape to guide flow of the deposition material915 in the X-axis and Y-axis directions.

As described above, the thin film deposition apparatus 900 according tothe current embodiment of the present invention performs depositionwhile being moved relative to the substrate 400. In order to move thethin film deposition apparatus 900 relative to the substrate 400, thepatterning slit sheet 950 is separate from the substrate 400 by apredetermined distance.

In particular, in a conventional deposition method using an FMM,deposition is performed with the FMM in close contact with a substratein order to prevent formation of a shadow zone on the substrate.However, when the FMM is used in close contact with the substrate, thecontact may cause defects. In addition, in the conventional depositionmethod, the size of the mask has to be the same as the size of thesubstrate since the mask cannot be moved relative to the substrate.Thus, the size of the mask has to be increased as display devices becomelarger. However, it is not easy to manufacture such a large mask. Inorder to overcome this problem, in the thin film deposition apparatus900 according to the current embodiment of the present invention, thepatterning slit sheet 950 is disposed to be separate from the substrate400 by a predetermined distance.

As described above, according to the present invention, a mask is formedto be smaller than a substrate, and deposition is performed while themask is moved relative to the substrate. Thus, the mask can be easilymanufactured. In addition, defects caused due to the contact between asubstrate and an FMM, which occurs in the conventional depositionmethod, may be prevented. In addition, since it is unnecessary to usethe FMM in close contact with the substrate during a deposition process,the manufacturing speed may be improved.

In the thin film deposition assembly 900 according to the currentembodiment of the present invention, each of the patterning slits 951includes a plurality of sub-slits 951 a and 951 b. As described above,one patterning slit 951 includes the plurality of sub-slits 951 a and951 b, and the sub-slits 951 a and 951 b are arranged so that patternsformed by the plurality of sub-slits 951 a and 951 b overlap each other.Then, a desired pattern may be obtained. Since this is described indetail in the previous embodiment, and thus, detailed descriptions arenot provided here.

FIG. 12 is a schematic perspective view of the thin film depositionapparatus 900 according to another embodiment of the present invention.Referring to FIG. 12, the thin film deposition apparatus 900 accordingto the current embodiment of the present invention includes a depositionsource 910, a deposition source nozzle unit 920, and a patterning slitsheet 950. In particular, the deposition source 910 includes a crucible911 that is filled with the deposition material 915, and a heater 912that heats the crucible 911 to vaporize the deposition material 915,which is contained in the crucible 912, towards a side of the crucible911, and in particular, towards the deposition source nozzle unit 920.The deposition source nozzle unit 920, which has a planar shape, isdisposed at a side of the deposition source 910. The deposition sourcenozzle unit 920 includes a plurality of deposition source nozzles 921arranged in the Y-axis direction. The patterning slit sheet 950 and aframe 955 are further disposed between the deposition source 910 and thesubstrate 400, and the patterning slit sheet 950 includes a plurality ofpatterning slits 951 arranged in the X-axis direction. In addition, thedeposition source 910, the deposition source nozzle unit 920, and thepatterning slit sheet 950 are connected to each other by the connectionmember 935.

In the current embodiment of the present invention, the plurality ofdeposition source nozzles 920 formed on the deposition source nozzleunit 921 are tilted at a predetermined angle. In particular, thedeposition source nozzles 921 may include deposition source nozzles 921a and 921 b which are arranged in two rows, which are alternatelyarranged with each other. Here, the deposition source nozzles 921 a and921 b may be tilted at a predetermined angle on an X-Z plane.

That is, in the current embodiment of the present invention, thedeposition source nozzles 921 a and 921 b are arranged in tilted statesat a predetermined angle. Here, the deposition source nozzles 921 a in afirst row may be tilted toward the deposition nozzles 921 b in a secondrow, and the deposition source nozzles 921 b in the second row may betilted toward the deposition source nozzles 921 a in the first row. Thatis, the deposition source nozzles 921 a arranged in the row at the leftside of the patterning slit sheet 950 are arranged to face the rightside of the patterning slit sheet 950, and the deposition source nozzles921 b arranged in the row at the right side of the patterning slit sheet950 are arranged to face the left side of the patterning slit sheet 950.

FIG. 13 is a graph illustrating a thickness distribution of a depositionlayer formed on the substrate 400 when the deposition source nozzles 921were not tilted, in the thin film deposition apparatus 900 according tothe current embodiment of the present invention, and FIG. 14 is a graphshowing a thickness distribution of a deposition layer formed on thesubstrate 400 when the deposition source nozzles 921 were tilted, in thethin film deposition apparatus 900 according to this embodiment of thepresent invention. Comparing the graphs of FIGS. 13 and 14 with eachother, the thickness of both sides of the deposition layer formed on thesubstrate 400 when the deposition source nozzles 921 are tilted isrelatively greater than that of both sides of the deposition layerformed on the substrate 400 when the deposition source nozzles 921 arenot tilted, and thus, the uniformity of the thin film is improved whenthe deposition source nozzles 921 a and 921 b are tilted.

Therefore, the deposition amount of the deposition material may beadjusted so that the difference between the thickness of the centerportion in the thin film and thickness of the both sides of the thinfilm formed on the substrate may be reduced and the entire thickness ofthe thin film may be constant, and moreover, the efficiency of utilizingthe deposition material may be improved.

As described above, the thin film deposition apparatus according toaspects of the present invention may be easily manufactured and may besimply applied to produce large-sized display devices on a mass scale.The thin film deposition apparatus may improve manufacturing yield anddeposition efficiency and may allow deposition materials to be reused.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

What is claimed is:
 1. A thin film deposition apparatus for forming athin film on a substrate, the apparatus comprising: a deposition sourcethat discharges a deposition material; a deposition source nozzle unitdisposed at a side of the deposition source and including a plurality ofdeposition source nozzles arranged in a first direction; and apatterning slit sheet disposed opposite to the deposition source nozzleunit and including a plurality of patterning slits arranged in a seconddirection perpendicular to the first direction, wherein: a deposition isperformed while the substrate or the thin film deposition apparatusmoves relative to the other in the first direction, the depositionsource, the deposition source nozzle unit, and the patterning slit sheetare formed integrally with each other, and each of the patterning slitsincludes a plurality of sub-slits.
 2. The thin film deposition apparatusof claim 1, wherein a gap between neighboring patterning slits isgreater than a gap between neighboring sub-slits included in onepatterning slit.
 3. The thin film deposition apparatus of claim 1,wherein the sub-slits are arranged so that at least a part of a patternthat is formed of the deposition material discharged from one of thesub-slits included in one patterning slit towards the substrate and atleast a part of a pattern that is formed of the deposition materialdischarged from the other of the sub-slits included in that patterningslit towards the substrate may overlap each other.
 4. The thin filmdeposition apparatus of claim 1, wherein the plurality of sub-slits areformed as rectangles arranged in parallel with each other.
 5. The thinfilm deposition apparatus of claim 1, wherein the plurality of sub-slitsare holes arranged in a plurality of rows which are parallel with eachother.
 6. The thin film deposition apparatus of claim 1, wherein thedeposition source and the deposition source nozzle unit, and thepatterning slit sheet are connected to the other by a connection member.7. The thin film deposition apparatus of claim 6, wherein the connectionmember guides movement of the discharged deposition material.
 8. Thethin film deposition apparatus of claim 6, wherein the connection memberseals a space between the deposition source and the deposition sourcenozzle unit, and the patterning slit sheet.
 9. The thin film depositionapparatus of claim 1, wherein the thin film deposition apparatus isseparate from the substrate by a predetermined distance.
 10. The thinfilm deposition apparatus of claim 1, wherein the deposition materialdischarged from the thin film deposition apparatus is continuouslydeposited on the substrate while the substrate or the thin filmdeposition apparatus is moved relative to each other in the firstdirection.
 11. The thin film deposition apparatus of claim 1, whereinthe patterning slit sheet of the thin film deposition apparatus issmaller than the substrate.
 12. The thin film deposition apparatus ofclaim 1, wherein the plurality of deposition source nozzles are tiltedat a predetermined angle.
 13. The thin film deposition apparatus ofclaim 12, wherein the plurality of deposition source nozzles includesdeposition source nozzles arranged in two rows formed in the firstdirection, and the deposition source nozzles in the two rows are tiltedto face each other.
 14. The thin film deposition apparatus of claim 12,wherein the plurality of deposition source nozzles include depositionsource nozzles arranged in two rows formed in the first direction, thedeposition source nozzles arranged in the row located at a first side ofthe patterning slit sheet are arranged to face a second side of thepatterning slit sheet, and the deposition source nozzles arranged in theother row located at the second side of the patterning slit sheet arearranged to face the first side of the patterning slit sheet.